Process for sweetening sour hydrocarbon oil



Fermented Feb. 13, A945 IPEQCEES FUR SWEETENING SQUB HYDRUCARJBGN GILGeorge R. Gilbert, Elizabeth, N. 5., asaignor to Standard @ilDevelopment Company, a corporation 02 Delaware No Drawing. AppiicationDecember 11, 119412,

Beriai No. 468,685

4 Claims.

This invention relates to treating hydrocarbon fluids and moreparticularly relates to finishing or treating hydrocarbons such asgasoline and kerosene to remove undesirable components therefrom.

One of the steps used in finishing hydrocarbons is the removal orconversion of malodorants such as mercaptans into other compounds whichhave no odor. The usual doctor sweetening process converts mercaptansinto disulfldes and unless extreme care is used the total sulfur in thetreated hydrocarbon is increased. Various catalytic processes have beenused for removing sulfur from hydrocarbon products. Bauxite has beenused to reduce mercaptans and total sulfur in hydrocarbon products butin such a process high temperatures are necessary to obtain adequateremoval of the mercaptan and total sulfur. At lower temperaturesrelatively large volumes of bauxite per volume of oil treated arenecessary.

My invention comprises an improvement on the bauxite treatment ofhydrocarbons such as kerosene or gasoline. According to my inventionsour hydrocarbons are sweetened by using granular bauxite containing orimpregnated with lead oxides. I have found that bauxite impregnated withlead oxides sweetens sour hydrocarbons to a greater extent thanactivated granular bauxite which has not been so impregnated and thesweetening process is carried out at about room temperature and withrelatively small amounts of bauxite impregnated according to myinvention.

More specifically, I mix or agitate a sour hydrocarbon oil such askerosene with a sodium plumbite solution for a time sufiicient to obtainsoluble lead mercaptides and then percolate thelead-mercaptide-containing hydrocarbon mixture through a quantity ofbauxite which has been activated. The first volumes of the filtrate fromthe percolation vessel or zone are lead free and sweet but eventuallythe hydrocarbon material coming through contains lead compoundsindicating that the bauxite is saturated with lead mercaptides. Whenthis occurs the flow of hydrocarbon through the percolation zone orpercolator is stopped and the bauxite in the percolator is purged freeof adsorbed hydrocarbons. The purged bauxite is then burned in thepresence of air to reduce the lead mercaptides to lead oxides and inthis way the bauxite is impregnated with lead oxides. This impregnatedbauxite is superior to bauxite not so treated.

The invention will now. be more specifically described. In treating andfinishing hydrocarbon oils such as kerosene and gasoline it isnecessaryto remove evil smelling sulfur compounds or to convert sulfurcompounds to other compounds which do not have an objectionable odor. Myinvention specifically relates to producing an activated bauxiteimpregnated with lead oxide or oxides and using such an impregnatedbauxite for treating sour hydrocarbons. While other processes ofimpregnating oxides may be used, I prefer to saturate an activatedbauxite with lead mercaptides, oxidize the lead mercaptides to leadoxides and then use this impregnated bauxite to treating sourhydrocarbon oils.

The preparation of the granular bauxite impregnated with lead oxideswill be first described. Iagitatea sour hydrocarbon such as kerosenecontaining about 36 milligrams of mercaptan sulfur per 100 cc. ofkerosene and about 0.155% by weight of total sulfur with a. sodiumplumbite solution for a time sufficient to convert all mercaptan sulfurin the kerosene to soluble lead mercaptides. The sodium plumbitesolution is the usual doctor sweetening reagent known in the art. Duringthis treatment the temperature is about F. and the time of treating isabout 5 minutes. The hydrocarbon mixture containing lead mercaptides isthen percolated through a quantity or bed of bauxite which has beenactivated by heating in the presence of air for a period of about 3hours at a temperature between about 750 F. and 900 F. Duringpercolation the temperature of the bauxite is about 85 F.

The first few volumes of filtrate come through the activated bauxitelead free and sweet but eventually after about 1 to 3 volumes ofkerosene per volume of bauxite have been passed through the bauxite, thekerosene contains lead compounds indicating that the bauxite issaturated with lead mercaptides. The flow of kerosene through thebauxite is then stopped and the bauxite is purged with an inert gas suchas steam, hydrocarbon gas, flue gas or the like to remove adsorbedhydrocarbons from the bauxite which may be separately recovered ifdesired.

The bauxite containing the lead mercaptides is then burned by blowingair through the bauxite for about 3 hours at a temperature between about750 F. and 900 F. and in this way I obtain a bauxite impregnated withlead oxides. While I am not certain of the actual composition of thelead oxide or oxides, I believe that I obtain mainly lead oxide (PbO) ora mixture of lead oxides. such as PbO, PbOz, PbcOa, Pb304.

The bauxite impregnated with lead oxides according to my inventiondiffers from the usual activated bauxite and is an improvement thereoveras shown by the following data.

Example 1 cc. of kerosene and about 0.077 weight per cent oi totalsulfur.

Eaompie ii I percoiated about 3 volumes or kerosene contaming about 36milligrams of mercaptan sulfur per 100 cc. oi kerosene and about 8.155weight per cent of total sulfur to about 1 volume of bauxite whichdiffered from the bauxite used in Example 1 in that it was impregnatedwith lead oxides according to my invention, under the same rateconditions and temperature as employed in Example 1. I blended the 3volumes together and the finally treated kerosene had less than about0.5 milligram oi mercaptan sulfur per 100 cc. of kerosene and only about0.067 weight per cent total sulfur.

From the above examples, it will be seen that the bauxite preparedaccording to my invention and containing lead. oxide or oxides sweetensthe hydrocarbon oil and reduces the total suliur more eiiectively thanbauxite prepared according to customary procedure and the sweetening andreduction in sulfur can be eiiected at a relatively low temperature.

In the preparation or my impregnated bauxite it will be seen that Ifirst use an activated bauxite and the first few volumes of oil or abouti to 3 volumes of oil per volume of bauxite coming from the percolatorare lead free and sweet. The oil which is first passed through theactivated bauxite is preferably separately collected and blended withthe sweetened product resulting from the treatment of oils with mybauxite imprefinated with lead oxides. In this way I can also sweetenand remove sulfur from a portion or the oil with the activated bauxitebefore the bauxite is impregnated according to my invention.-

When my impregnated bauxite becomes contaminated in use, it is onlynecessary to stop the flow of oil, purge the contaminated bauxite in thevessel with a purging gas and then burn the impregnated bauxite with airto remove contaminants and leave lead oxides on the bauxite. The bauxiteis regenerated in situ in the treating vessel.

While I have set forth the best form of my invention known to me at thistime and have given two examples of treating sour kerosene, it is to beunderstood that changes and modifications may be made in my inventionand that the examples are by way or illustration only and specificdetails may be varied when using diflerent stocks.

I claim:

1. A process or treating sour hydrocarbon liquids which comprisespassing the sour liquid hydrocarbon containing mercaptans and sulfurover a calcined contact agent comprising bauxite and a lead oxide, at arelatively low temperature and recovering a sweetened liquidhydrocarbon, the contact agent being produced by impregnating bauxitewith lead mercaptide and oxidizing the lead mercaptide to lead oxide.

2. A process of treating sour hydrocarbons which comprises passing asour hydrocarbon containing mercaptans and sulfur over a calcinedcontact agent comprising bauxite impregnated with lead oxide, at arelatively low temperature and recovering a sweet hydrocarbon, thecontact agent being produced by impregnating an activated bauxite withlead mercaptides and oxidizing the mercaptides to lead oxides.

3. A process according to claim 2 wherein the hydrocarbon during thetreatment is at a temperature of about 85 F.

4. Process according to claim 1 in which the contact agent is preparedby impregnating bauxite with lead mercaptide and heating the same in thepresence of air to oxidize the mercaptide to an oxide.

GEORGE R. GILBERT.

